Denis Defreyne

[dəˈni] • pronouns: he/him
+49 1573 1969 173
Berlin, Germany

I am a software engineer with extensive experience in backend and frontend development. I am comfortable with infrastructure, security, and reliability topics.

I excel at technical writing and have a solid sense of visual design and UX.


Aug 2022 –

Staff software engineer

  • Created tooling to automate onboarding across all products of all teams
  • Architected and prototyped a cross-project access management (authorization) solution
  • Guided teams to adopt state-of-the-art software delivery practices (CI/CD), significantly speeding up releases and reducing overhead to a minimum
  • Mentored junior coworkers to bring them to a more senior level
Jul 2021 –
Jun 2022,

Senior software engineer

  • Prototyped a recommender system for suggested products
  • Converted a legacy PHP platform into a Ruby on Rails one
Feb 2021 –
Jun 2021,

Software engineer

  • Sped up build pipelines and increased delivery resilience by improving developer tooling
Jul 2020 –
Dec 2021,

Software engineer, co-founder

  • Led the technical design and implementation of a privacy-first contact-sharing solution for Berlin nightclubs
Jul 2019 –
Dec 2020,

Senior Software engineer

BCG Digital Ventures
  • Defined the technical direction for the internal tools team, striking a balance between business needs and long-term maintenance
  • Migrated a legacy system onto a modern frontend stack (React and Type­Script), boosting development speed and quality
  • Brought consistency to the design system, and improved accessibility
Nov 2017 –
Jun 2019,

Senior Software engineer

  • Brought consistency to the company’s infrastructure using Terraform and Ansible, slashing infrastructure operating costs by 40–50%
  • Introduced monitoring and alerting using Prometheus and Grafana
  • Tightened security of applications, services, processes, and infrastructure
Jun 2013 –
Nov 2017,

Software engineer

  • Built infrastructure for the On SoundCloud partner program, including a flexible logic engine to handle frequently-changing business needs
  • Ran workshops around incident response
  • Set up a central repository for organization-wide technical documentation
  • Improved and expanded the customer support’s tooling and processes
Sep 2010 –
May 2013,

Software engineer

MediaGeniX NG
  • Expanded the broadcasting solution for VIMN subsidiaries such as MTV, Comedy Central and Nickelodeon for divisions in Europe and Southeast Asia
2007 –

Software developer intern

  • At Cyan Worlds: modernized web sites, improved SEO, set up translation workflows across seven languages
  • At Netlog, optimized an abuse-detection system for social networks
  • At dotProjects, developed a web-based machine translation system for large documents

Core skills

Natural languages

English: fluent
Dutch: fluent
German: conversational

Programming languages

expert: Ruby, HTML, CSS
advanced: JavaScript, Type­Script, Go
intermediate: Java, Python, SQL
beginner: Rust, Clojure


advanced: React, Ruby on Rails
intermediate: PostgreSQL, MySQL
beginner: Tableau, Node.js

Community involvement


Creator and maintainer of Nanoc, a powerful static-site generator, used at GitHub, at GitLab, at PayPal, for Prometheus, at FOSDEM, for Atom, at Disney, and in many more places.

Open-source projects

Creator and maintainer of several open-source projects, including cri, ddmemoize, and ddmetrics.


I have mentored a diverse group of people as part of CoderDojo, RailsGirls, and SoundCloud’s internship programs.

Public speaking

I regularly give talks, of which Code as data (2018), How to memoize (2018), and Let’s write a parser (2016) are my personal favorites.


Master of Computer Science (Ghent University)

Dissertation: Design of a recommendation system for offering services on social-network sites

Bachelor of Informatics (Ghent University)